Helmet face shield

ABSTRACT

A face shield for headgear comprises a generally transparent main lens, adapted for engagement to the headgear. The main lens comprises a curved inner and outer main lens surfaces and has a central recessed portion with a curved recessed inner lens surface and a curved recessed outer lens surface. The recessed inner lens surface and the recessed outer lens surface are respectively offset from the curved inner and outer main lens surfaces. The recessed portion is adapted to receive a secondary lens such that a sealed air gap is formed between the secondary lens and the main lens, thereby forming a sealed double pane lens having condensation reduction properties.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/769,979, filed on Feb. 3, 2004, and which claims priority on USProvisional Patent Application No. 60/444,159, filed on Feb. 3, 2003.The entire contents of both of which are incorporated herein byreference.

TECHNICAL FIELD

The present invention relates generally to shields for protectivehelmets used for snowmobiling, motorcycle riding and the like. Moreparticularly, the present invention relates to a protective face shieldhaving a removable lens portion.

BACKGROUND OF THE INVENTION

Protective helmets such as, for example, those used for snowmobiling andmotorcycle riding, are well known. They typically include a generallytransparent face shield or lens. Two distinct types of helmet faceshields are typically employed. Shields having a single pane lens aregenerally used in warmer environmental conditions. Face shields having adual lens construction comprising an inner lens and an outer lens, aremost often used in colder and more humid conditions. In cold weather,single pane lenses tend to fog up, consequently impairing the rider'svision. However, single pane lenses generally provide better visualproperties in comparison with double pane lenses, the thinner singlelens causing less optical distortion. Nonetheless, double pane lensesare almost universally used in colder climatic conditions, in order tohelp keep the face shield substantially free of condensation.

Many kinds of face shields employ additional techniques to furtherattempt to prevent fogging. These include lenses having an electricalheating system, wherein an inner lens surface is coated with anelectrically conductive film and two electrodes, on opposite edges ofthe lens, permit an electrical current to flow across the film coveringthe lens, thereby inhibiting condensation build up thereon. Otheranti-condensation methods are also well known, such as those providingdirected ventilation along an inner surface of the lens or employing ahydrophilic anti-condensation layer, in the form of a sheet, film orother covering, that is fitted within an outer lens. These additionalanti-condensation devices are typically used in combination with adouble-paned lens.

Most face shields having such a double pane construction comprise twolenses that are contained within a separately constructed perimeterframe, which provides support for the double-paned lens and permitspivotable attachment thereof to the helmet. Double pane lens assembliesare significantly thicker than single paned lenses, and their attachmentto some helmets which are not specifically designed to accommodate themcan accordingly be difficult without the rather bulky perimeter frame.These face shield perimeter frames can significantly add to themanufacturing cost of the face shield assembly, unduly add bulk andweight to the helmet, and contribute to aerodynamic inefficiencies andincreased wind noise.

Most known face shields that do not comprise perimeter frames, and havedouble pane lenses or have a hydrophilic layer superimposed on a singlelens, do not permit removal of one of the lens panes or theanti-condensation layer. However, it has been known to provide such aframe-free face shield for a protective helmet having a detachablyengaged inner lens. U.S. Pat. No. 5,765,235 issued Jun. 16, 1998 toDerek Leslie Arnold, for example, discloses an anti-condensation visorcomprising an outer visor for attachment to a helmet and an inner visor,made of hydrophilic material, detachably fitted against the inside wallof the outer visor and held there against by at least one mechanicalretaining element. The inner visor must rest against the inside wall ofthe outer visor in such a way that no space is left between them. U.S.Pat. No. 4,584,721 issued Apr. 29, 1986 to Tamenobu Yamamoto, disclosesa helmet face shield having an electric heating device for preventingfogging. The device comprises a removable inner lens piece attachedbehind the outer helmet lens. The inner lens piece is generally engagedto the outer lens by a mechanical engagement element such as a snapfastener.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improved faceshield for a protective helmet.

It is another object of the present invention to provide a face shieldhaving a frameless main lens capable of receiving a second lens portionthat can be sealed to the main lens with an air gap therebetween tocreate a double pane lens.

The present invention permits an inner lens to be engaged to an outerlens such that it is offset therefrom but sealed thereto. The presentinvention further permits the single pane lens to be converted into adouble pane lens having improved anti-condensation properties providedby an air gap trapped between the inner and outer lenses of the sealeddouble pane lens.

Therefore, in accordance with the present invention, there is provided aface shield for headgear comprising: a generally transparent main lensadapted for engagement to the headgear; the main lens comprising curvedinner and outer main lens surfaces and having a central recessedportion, the recessed portion having a recessed curved inner lenssurface and a recessed curved outer lens surface, the recessed innerlens surface and the recessed outer lens surface being respectivelyoffset from the curved inner and outer main lens surfaces; and therecessed portion being adapted to receive a secondary lens therein suchthat a sealed air gap is formed between the secondary lens and the mainlens, thereby forming a sealed double pane lens having anti-condensationproperties.

There is also provided, in accordance with the present invention, a faceshield for headgear comprising: a generally transparent main lensadapted for engagement to the headgear; the main lens comprising curvedinner and outer main lens surfaces and having a central recessedportion, the recessed portion having a recessed curved inner lenssurface and a recessed curved outer lens surface, the recessed innerlens surface and the recessed outer lens surface being respectivelyoffset from the curved inner and outer main lens surfaces; and asecondary lens, selectively engageable within the recessed portion ofthe main lens such that a sealed air gap is formed between the secondarylens and the main lens, thereby selectively forming a sealed double panelens having anti-condensation properties.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present invention will becomeapparent from the following detailed description, taken in combinationwith the appended drawings, in which:

FIG. 1 is a perspective view of a face shield according to the presentinvention engaged to a protective helmet;

FIG. 2 is an exploded perspective view of the helmet face shield of FIG.1, showing a main lens and a secondary lens;

FIG. 3 is a front elevation view of the helmet face shield of FIG. 1;

FIG. 4 is a horizontal cross-sectional view taken along line 4-4 of FIG.3; and

FIG. 5 is a perspective view of an alternate embodiment of the secondarylens for engagement with the main lens of FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, the face shield 10 is adapted to be engaged to, andused with, headgear such as a protective helmet 13 as conventionallyused for motorcycle riding, snowmobiling, flying and the like. The faceshield 10 is also adapted for use with other protective headgearcomprising a transparent face shield, such as paintball masks forexample. The face shield 10 comprises primarily a generally transparentmain lens 12, thereby providing a single pane lens that does not requirea perimeter frame for support or engagement to the protective helmet 13.The main lens 12 is preferably a moulded plastic one-piece element,having a thickness of approximately 2 mm (about 0.07874 inches). Themain lens 12 is preferably injection moulded, however othermanufacturing techniques could also be used, such as drape or vacuummoulding for example. One skilled in the art will also appreciate thatthe main lens 12 can have a non-uniform thickness throughout.Particularly, as is known in the art, the lens can be formed such thatit is thickest at a center point thereof and becomes gradually thinnertowards each edge of the lens. This causes the least distortion of lightpassing through the lens, enabling the single paned main lens 12 toprovide substantially distortion free optical characteristics. The mainlens 12 is preferably formed having a curvature about a substantiallyvertical axis that substantially corresponds to that of the protectivehelmet 13 to which it is to be engaged, however it generally comprises asubstantially semi-circular shape. The main lens 12 can also beoutwardly convex throughout the semi-circular length thereof, having asecond curvature about a substantially horizontal axis, creating acomplex lens curvature. The curved main lens 12 comprises a curved innermain lens surface 14 and a curved outer main lens surface 16.

The main lens 12 comprises a central recessed portion 18, having arecessed curved inner surface 20 and a recessed curved outer surface 22,the recessed portion 18 being preferably outwardly offset from the mainlens 12. The recessed portion 18 preferably comprises most of the mainlens 12, such that the recessed portion 18 substantially covers theentire visual field of the user. The offset edges 24 of the recessedportion 18 are therefore located just at the edge or just outside theviewing field of the user looking through the face shield 10 when it isdisposed in a normal operating position on the protective helmet 13. Thesize and shape of the recessed portion 18 preferably corresponds to aforward opening 15 in the protective helmet 13, such that the offsetedges 24 of the recessed portion 18 are near the perimeter of theopening 15 in the helmet 13.

As seen in FIG. 1, helmet engaging members 28 are fixed to the main lens12 at remote mounting ends 16 thereof. The helmet engaging members 28are fixed to the remote ends 26 of the main lens 12, and are preferablypivotally engageable to the sides of the protective helmet 13, such thatthe entire face shield 10 can be pivoted to open or close the opening 15in the helmet 13. The main lens 12 can thus be used alone as a singlepane helmet visor when required. This may be most desirable in warmenvironmental operating conditions, and for particular applications,such as for motorcycle riding for example.

However, in colder conditions and applications, such as for snowmobilingfor example, a single pane helmet lens tends to fog up. As such, themain lens 12 of the face shield 10 can be modified to provide a doublepane lens 19, as seen in FIGS. 3 and 4, if desired. A generallytransparent secondary lens 30, best seen in FIG. 2, is receivable intothe recessed portion 18 of the main lens 12, such that a sealed doublepane helmet lens 19 is formed. The secondary lens 30 comprises an innercurved lens surface 32 and an outer curved lens surface 34. Thesecondary lens 30 is generally formed with a radius of curvaturesomewhat similar to that of the main lens 12, however the secondary lens30 is preferably provided with a radius of curvature that is slightlylarger than that of the main lens 12. This requires a slight deflectionof the secondary lens 30 for it to fit within the recessed portion 18,providing a slight pre-tension in the secondary lens 30, and therebyhelping it to remain engaged within the recessed portion 18. Thesecondary lens 30 is positioned within the recessed portion 18 such thatan air gap 40 remains between the outer curved lens surface 34 of thesecondary lens 30 and the curved inner main lens surface 14 of the mainlens 12. The secondary lens 30 preferably has a lens thickness that isless than the offset distance of the recessed portion 18 from the curvedlens surfaces 14,16 of the main lens 12. The common distance that therecessed curved inner lens surface 20 and the recessed curved outer lenssurface 22 are respectively offset from the inner main lens surface 14and outer main lens surface 16 is preferably approximately 3 mm (about0.11811 inch). If a secondary lens 30 having a 2 mm (about 0.07874 inch)thickness is used, for example, the air gap 40 will be approximately 1mm (about 0.03937 inch) wide. It will be understood, however, that otherair gap widths and secondary lens thicknesses can be similarly used toachieve the same effect.

Unlike many double paned lens assemblies of the prior art, the presentdouble pane lens 19 does not require a separately constructed perimeterframe which provides support for the double paned lens assembly, as thesecondary lens 30 is retained within the recessed portion 18 of the mainlens 12. The elimination of the perimeter frame results in reducedmanufacturing, and subsequently retail, costs, a reduction in theoverall weight and size of the face shield 10 having the double panelens 19, and improved aerodynamics. By smoothly integrating theframeless main lens 12 into the helmet 13 such that the outer main lenssurface 16 is substantially flush with an outer surface of the helmet13, reduced aerodynamic drag and noise is provided.

The secondary lens 30 preferably has a gasket seal 36 disposed aroundthe perimeter thereof. The gasket seal 36 is preferably disposed on oneof the outer curved lens surface, and a peripheral edge defined betweenthe inner curved lens surface 32 and the outer curved lens surface 34.When disposed on the outer curved lens surface, the perimeter gasketseal 36 helps to space the secondary lens 30 away from the main lens 12when positioned within the recessed portion 18, ensuring that a fairlyconstantly spaced air gap 40 is maintained therebetween. The gasket 36also seals the air gap 40, ensuring that a sealed double pane lens 19 ismaintained. While the gasket seal 36 is preferably disposed on thesecondary lens 30 before insertion of the secondary lens 30 into therecessed portion 18 of the main lens 12, it can similarly be insertedindependently into the recessed portion 18 before the secondary lens 30is positioned therein. The gasket seal 36 is preferably made ofgenerally transparent material, such that vision at the offset edges 24between the secondary lens 30 and the main lens 12 is not obscured. Thegasket seal 36 is preferably as transparent as possible, but materialsthat are merely translucent can also be employed. A generallytransparent silicone bead, for example, can be used as the gasket seal36. Such a silicone bead is preferably sufficiently compressible whenthe secondary lens 30 is engaged within the recessed portion 18, suchthat a slight vacuum is created between the secondary lens 30 and themain lens 12, thereby holding the secondary lens 30 in place therein.The slightly larger radius of curvature of the secondary lens 30relative to the main lens 12 further provides frictional retention ofthe secondary lens 30 within the recessed portion 18 of the main lens12. Other substantially permanent retention means, such as adhesives orsealing tape for example, can be used to fix the secondary lens 30within the recessed portion 18 and to seal the air gap 40 therebetween.

Alternately, other temporary retention means can be used which permitthe user to add and/or remove the secondary lens 30 from the main lens12 whenever required. This may be desirable, for example, if aprotective helmet 13 having the face shield 10 is to be used both formotorcycle riding in warm weather and snowmobile riding in cold weather.In such a case, the main lens 12 is preferably used by itself in thewarmer conditions to provide improved visibility. The secondary lens 30may be subsequently inserted within the recessed portion 18 of the mainlens 12 to form the double pane lens assembly 19 in colder conditions,to provide improved anti-condensation properties. In such a case, thesecondary lens 30 is therefore engaged within the recessed portion 18,using removably fastenable members such as temporary adhesives,removable two-sided tape, or hook and loop fasteners for example. Withsuch temporary fastening means, the secondary lens 30 nonethelesspreferably forms a seal with the main lens 12 such that the sealed airgap 40 is provided therebetween in the recessed portion 18. Thetemporary fastening means may provide the sealing themselves, or anadditional seal may be provided in addition to the temporary fasteningmeans.

The addition of the secondary lens 30 to the main lens 12 can be doneeither by the user as an after-market upgrade, or by the manufacturer,permitting a more cost effective way of producing different face shieldsfor various applications. Particularly, rather than producing twodistinct product lines, a common main lens 12 can be used alone or incombination with a secondary lens 30 to create a double pane lens 19.For example, the main lenses 12 can be either sold alone as a singlepane face shield, or be permanently assembled with the secondary lens 30in the factory for sale as a sealed double pane lens 19 particularlyadapted for cold climatic applications. The secondary lenses 30 couldalso be sold independently, for selected assembly by the user forconverting a single pane lens into a cold weather, sealed double panelens 19. The secondary lens 30 can either be as transparent as the mainlens 12, or can comprise a tint, such that a shaded double pane lens 19is created.

The seal formed between the secondary lens 30 and the main lens 12,ensuring the sealed air gap 40 therebetween, maintains thermalproperties of the double pane lens 19 formed by the assembly of the mainlens 12 and the secondary lens 30. Such a sealed, dual plane lens 19 ismuch more effective at preventing condensation at low temperatures thansingle paned lenses or double lenses that do not form a sealed air gaptherebetween.

A secondary lens 50 of an alternate embodiment, shown in FIG. 5, isalternately used in place of the secondary lens 30 for engagement withthe main lens 12 to form the sealed dual plane lens 19. The alternatesecondary lens 50 is similarly shaped to the secondary lens 30, and isequivalently receivable into the recessed portion 18 of the main lens12. The secondary lens 50 is generally transparent, although cancomprise a tint if desired, and comprises a curved inner lens surface 52and a curved outer lens surface 54. The secondary lens 50 preferablyincludes a perimeter seal 56 thereon, disposed either about a perimeterof the curved outer lens surface 54 or on the perimeter edge between theinner curved lens surface 52 and the curved outer lens surface 54. Thesecondary lens 50 differs from the secondary lens 30 in that itcomprises an electrical heating system 60 which provides additionalanti-fogging capabilities. The electrical heating system 60 generallyincludes at least two elongated electrodes, normally an upper electrode62 extending along an upper margin of the secondary lens 50 and a lowerelectrode 64 extending along a lower margin of the secondary lens 50.While the upper and lower electrodes 62,64 are preferably located on theouter lens surface 54, they can be alternately disposed on the innerlens surface 52 without significantly altering their anti-condensationeffect. Between the upper and lower electrodes 62,64 is provided atransparent electro-conductive film 68 substantially covering the entireouter lens surface 54. The transparent electro-conductive film 68 ispreferably a thin layer of indium tin oxide (ITO), applied by sputtercoating on the outer curved lens surface 54. Such an ITO coatingprovides high visible light transmission, low reflectivity andsubstantially uniform electrical conductivity. Insulated electrodecontacts 66 are in electrical contact with the upper and lowerelectrodes 62,64 and extend through the secondary lens 50 to the innerlens surface 52. Conductors (not shown) linked to a power supply canthen be engaged to the electrode contacts 66, such that power issupplied across the upper and lower electrodes 62,64, resulting in anelectrical flow across the electro-conductive film 68. The conductorscan comprise wires or another electro-conductive film, such as anelectrically conductive silk screen ink, for example, formed on theinner lens surface 52. Another transparent electro-conductive film onthe inner lens surface 52 may be used as the conductor linking the powersupply to the electrode contacts 66. This eliminates any possible visionimpeding elements being located on the lens surfaces. Such a strip oftransparent ITO film extends along the inner main lens surface 14 of themain lens 12 and inner lens surface 52 of the secondary lens 50, linkinga connection to the power supply within the helmet attachment members 28to the electrode contacts 66 on the secondary lens 50. Resistance to theflow of electricity across the electro-conductive film 68, between theupper and lower electrodes 62,64 on the outer lens surface 54, causesheat. This heating of the secondary lens 50 thereby further helps toprevent or reduce the formation of fog, frost and ice on the sealeddouble pane lens assembly 19, comprising the main lens 12 and thesecondary lens 50. Much as the secondary lens 30, the alternatesecondary lens 50 having the electrical heating system 60 can be eitherpermanently fixed within the recessed portion 18 of the main lens 12, orcan be selectively removable therefrom as described above. Although theelectrical heating system 60 is described herein as being preferablyengaged on the secondary lens 50, it is to be understood that it canalso be disposed on the main lens 12, and particularly on the recessedcurved inner surface 20.

The frame-less face shield 10 according to the present invention hasgreat versatility. The main lens 12 can be used alone as a single pane,warm weather shield. When required, this can be converted into a coldweather, sealed double pane lens 19 with the addition of one of thesecondary lenses 30 or 50 into the central recessed portion 18 of themain lens 12, providing a sealed air gap 40 therebetween. This providesa face shield having a thermal barrier, the double pane lens 19providing improved anti-condensation properties at low temperatures. Thebest anti-condensation abilities of the face shield 10 are provided whenusing the alternate secondary lens 50 having the electrical heatingsystem 60 therein, which may be suited for very cold environmentalconditions. The face shield 10 can therefore be selectively adapted fordifferent uses and different environmental conditions as required,whether before consumer sale or after-market.

It is understood that numerous modifications to the face shieldaccording to the present invention will be evident to those skilled inthe art. Accordingly, the above description and accompanying drawingsshould be taken as illustrative of the preferred embodiments of theinvention and not in a limiting sense. It will be further understoodthat the present invention is intended to cover any variation, use oradaptation of the invention following, in general, the principles of theinvention and including such departures from the present disclosure ascome within known or customary practice within the art to which theinvention pertains, and as may be applied to the essential featuresherein set forth and as follow in the scope of the appended claims.

1. A face shield for headgear comprising: a generally transparent mainlens adapted for engagement to the headgear; the main lens comprisingcurved inner and outer main lens surfaces and having a central recessedportion, the recessed portion having a curved recessed inner lenssurface and a curved recessed outer lens surfaces the recessed innerlens surface and the recessed outer lens surface being respectivelyoffset from the curved inner and outer main lens surfaces; and therecessed portion being adapted to receive a secondary lens therein suchthat a sealed air gap is formed between the secondary lens and the mainlens, thereby forming a sealed double pane lens having condensationreduction properties.
 2. The face shield as defined in claim 1, whereinthe main lens is frame-less, being engageable to the headgear without aperimeter frame.
 3. The face shield as defined in claim 1, wherein theface shield comprises an electrical heating system providing furthercondensation reduction.
 4. The face shield as defined in claim 1,wherein the recessed portion substantially corresponds to an opening inthe headgear.
 5. The face shield as defined in claim 1, wherein edges ofthe recessed portion are disposed at least just outside a visual fieldof a user wearing the headgear.
 6. The face shield as defined in claim1, wherein the recessed portion is recessed outward relative to theinner main lens surface.
 7. The face shield as defined in claim 1,wherein the recessed inner lens surface and the recessed outer lenssurface are offset a common distance from the curved inner and outermain lens surfaces respectively.
 8. The face shield as defined in claim7, wherein the common distance is greater than a thickness of thesecondary lens.
 9. A face shield for headgear comprising: a generallytransparent main lens adapted for engagement to the headgear; the mainlens comprising curved inner and outer main lens surfaces and having acentral recessed portion, the recessed portion having a curved recessedinner lens surface and a curved recessed outer lens surface, therecessed inner lens surface and the recessed outer lens surface beingrespectively offset from the curved inner and outer main lens surfaces;and a secondary lens, selectively engageable within the recessed portionof the main lens such that a sealed air gap is formed between thesecondary lens and the main lens, thereby forming a sealed double panelens having condensation reduction properties when the secondary lens isengaged within the recessed portion.
 10. The face shield as defined inclaim 9, wherein the main lens is frame-less, being adapted forengagement to the headgear without a perimeter frame.
 11. The faceshield as defined in claim 9, wherein the face shield comprises anelectrical heating system providing further condensation reduction. 12.The face shield as defined in claim 11, wherein the secondary lenscomprises the electrical heating system.
 13. The face shield as definedin claim 12, wherein the electrical heating system is disposed on asurface of the secondary lens facing the air gap.
 14. The face shield asdefined in claim 9, wherein the secondary lens is replaceable.
 15. Theface shield as defined in claim 9, wherein a perimeter gasket forms aseal between the secondary lens and the main lens, thereby defining thesealed air gap therebetween.
 16. The face shield as defined in claim 15,wherein the perimeter gasket is disposed on the secondary lens.
 17. Theface shield as defined in claim 15, wherein the perimeter gasket issubstantially transparent.
 18. The face shield as defined in claim 15,wherein the perimeter gasket is compressible such that creation of aslight vacuum in the air gap is possible, enabling the secondary lens tobe retained in place within the recessed portion by suction.
 19. Theface shield as defined in claim 9, wherein the recessed portionsubstantially corresponds to an opening in the headgear.
 20. The faceshield as defined in claim 9, wherein edges of the recessed portion aredisposed at least just outside a visual field of a user wearing theheadgear.
 21. The face shield as defined in claim 9, wherein therecessed inner lens surface and the recessed outer lens surface arerespectively offset a common distance from the curved inner and outermain lens surfaces, the common distance being greater than a thicknessof the secondary lens.
 22. The face shield as defined in claim 9,wherein the recessed portion is recessed outward relative to the innermain lens surface.
 23. The face shield as defined in claim 9, whereinthe secondary lens has a radius of curvature greater than the main lens,such that the secondary lens is at least partly frictionally retainedwithin the recessed portion.